mtDNA haplogroup: dash in name

Question

I just noticed on the MTree at YFull that there are separate subclades

k1c1b  and  k1c1-b

within clade k1c1.  

I hadn't seen this before.  What is the significance of using a dash versus not?  Can I infer anything from the fact that both appended 'b', or is that just a quirk of these being the second subclades identified with a certain characteristic?

Answer 1

It's a very significant move by YFull to handle the problem of branch insertions farther up the mtDNA tree, which can happen anywhere an existing branch is associated with more than one mutation.  In this case, K1c1-b is a renaming of K1c1-C16301T, which would be hard to continue adding digits and letters to, for sub-branches.  YFull is actively identifying mutations and defining branches to associate with them.  They have added so many their tree is now at least double what it was, as the last version of PhyloTree.  Some sections have nearly 3 times as many branches.  Here is the K1c1 section.  So the hyphen is very significant, and K1c1b is a different branch than K1c1-b.

I've written about this here, including similar examples of renamings, plus the addition of ancient DNA.

Comments

To make sure I understand: in this case, K1c1a was identified first as including mutations C16301T and C7082T in addition to the K1c1 defining mutations -- presumably because all people at the time of the naming showed both mutations if they showed one of them.  Then later kits were found with just the C16301T mutation and not C7082T, so it is assumed C16301T occurred first in time and that there needed to be an intermediate branch there.  They called it K1c1-b, because K1c1-a had already been used for an branch upstream of K1c1h and the letter 'b' was next up?

Was it the first kit under K1c1-b* that led them to realize there needed to be a K1c1-b branch in the first place?  Or maybe it was the addition of the second kit (mine) that made them decide?

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Exactly!  You've perfectly described it.  And they've now inserted K1c1-c, before K1c1f and its new sub-branch.

I have never seen them add a branch based on only one sample, so I *believe* that's their rule, 2 or more samples before defining a new branch.  So yours initiated the new branch.  I've seen several cases similar to yours, although not added quite as quickly.  Some are added very quickly after the second sample is uploaded, like the new K1c1q (that's a Q).